The invention relates to a vacuum valve, comprising a valve body with a valve opening which has an axis and is surrounded by a valve seat, a closure member which is adjustable parallel to a longitudinal adjustment direction between an open position, in which said closure member opens up the valve opening, and an intermediate position, in which said closure member covers the valve opening but is raised from the valve seat, and which is adjustable parallel to a transverse adjustment direction between the intermediate position and a closed position, in which said closure member lies against the valve seat, a valve rod which supports the closure member and is mounted displaceably parallel to the longitudinal adjustment direction and parallel to the transverse adjustment direction, a displacement part which is connected rigidly to the valve rod, and a drive motor by which a drive shaft is rotatable about an axis of rotation lying parallel to the longitudinal adjustment direction in order to adjust the closure member between the open position, the intermediate position and the closed position.
Vacuum valves, in which, in order to close the vacuum valve, the closure member is first of all displaced in a longitudinal adjustment direction, which lies parallel to the valve rod, from an open position into an intermediate position, in which the closure member covers the valve opening, but is still raised from the valve seat, and, as a result, is placed against the valve seat in a transverse adjustment direction lying at an angle to the longitudinal adjustment direction, are also referred to as L valves.
In the case of a non-generic design of L valves, the valve rod is mounted pivotably about an axis, which is at right angles to the longitudinal adjustment direction, in order to permit the adjustment of the valve plate from its intermediate position into its closed position and back. In order to pivot the valve rod about the axis, use can be made here of slotted guides, as is known, for example, from U.S. Pat. No. 6,237,892 B1, U.S. Pat. No. 7,066,443 B2 or US 2012/0258242 A1.
In the case of L valves, in which, in order to adjust the closure member between the intermediate position and the closed position, a parallel displacement of the closure member in a transverse adjustment direction at an angle, in particular right angles, to the longitudinal adjustment direction takes place, according to a conventional embodiment drive elements for adjusting the closure member between the intermediate position and the closed position are arranged on a supporting unit supporting the closure member, wherein the supporting unit is located within the valve housing of the vacuum valve and is attached to a valve rod which is led out of the vacuum region of the vacuum valve. Such embodiments of L valves are disclosed, for example, in U.S. Pat. No. 6,056,266 A, U.S. Pat. No. 6,899,316 B2 and U.S. Pat. No. 7,611,122 B2.
WO 2010/034046 A1, U.S. Pat. No. 7,762,527 B2 and WO 2014/075757 A1 disclose L valves, in which a linear displacement of the closure member between the intermediate position and the closed position takes place, wherein both a drive for the adjustment of the closure member between the open and the intermediate position and a drive for the adjustment of the closure member between the intermediate and the closed position are arranged outside the vacuum. The valve rod supporting the closure member is displaceable in parallel here both in the longitudinal adjustment direction and in the transverse adjustment direction. In the case of the vacuum valve shown in WO 2014/075757 A1, a transmission part which is guided displaceably in the longitudinal adjustment direction by rod-shaped guide parts is attached here to the valve rod outside the vacuum, wherein the rod-shaped guide parts are displaceable in the transverse adjustment direction which is at right angles to the longitudinal adjustment direction. In order to displace the rod-shaped guide parts and therefore the valve rod in the transverse adjustment direction, use is made of pneumatic piston-cylinder units which act on the rod-shaped guide parts. In order to displace the valve rod in the longitudinal adjustment direction, use is likewise made of pneumatic piston-cylinder units which act on the transmission part.
A vacuum valve of the type mentioned at the beginning is disclosed in EP 2 749 798 A1. For opening and closing the vacuum valve, use is made of a drive motor which rotates a drive shaft which is designed in the form of a spindle and the axis of rotation of which lies parallel to the longitudinal adjustment direction. An adjustment member which is adjusted in the longitudinal adjustment direction by rotation of the spindle is connected via an oblique connection, in particular an oblique surface guide or a parallelogram guide, to a displacement part which, for its part, is connected rigidly to the valve rod, specifically outside the vacuum region. The displacement part is guided displaceably between a first position and a second position parallel to the longitudinal adjustment direction, and between a second position and a third position parallel to the transverse adjustment direction, via a guide, in particular slotted guide. In the first, second, and third positions of the displacement part, the closure member takes up its open, intermediate and closed position. In addition to the gear members for transmitting the drive force from the drive motor to the valve rod, this vacuum valve is therefore also provided with guide elements which are of relatively complex design, in particular in the form of a slotted guide, in order to guide the movements in the longitudinal adjustment direction and transverse adjustment direction.